MAR 15, 2016 04:29 PM PDT

The Biological Purposes of Tears

WRITTEN BY: Xuan Pham

Crying is a natural part of our human package. As babies, we cried to communicate needs for food and care. As adults, we cry less frequently and about different matters. And yes, even the manliest of men are susceptible to this condition - if the beginning of Up doesn't wet the eyes, just try slicing an onion for a few minutes.

Not all tears are the same. As it turns out, there are 3 different types of tears: basal, reflex, and emotional. Though all tears are formed by the lacrimal gland, each type is activated by different stimuli, and each function slightly differently. Basal tears are secreted daily to keep your cornea moistened and your eye from drying out. Reflex tears are stimulated by irritants, such as those found in onions and garlic. As reflex tears are mostly water, they function to dilute the irritants from your eyes so as to not impede your vision.

And lastly, emotional tears are ones that are activated by the limbic system and the hypothalamus as they process your intense happiness or sadness to an event. These tears actually contain the hormones adrenocorticotropic hormones (ACTH) and leucin-enkephalin, which is why a good cry can feel so cathartic sometimes. Unlike the basal and reflext tear types, scientists know less about why we cry for emotional reasons, though some hypothesize that it's one way for us to relieve stress.
About the Author
  • I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at TheGeneTwist.com.
You May Also Like
SEP 17, 2018
Videos
SEP 17, 2018
How THC Binds to Cannabinoid Receptors in the Brain
Seconds after marijuana is consumed it begins to affect your brain. The main cannabinoid produced by the cannabis plant is called THC (tetrahydrocanna...
SEP 20, 2018
Chemistry & Physics
SEP 20, 2018
"Silver Bullet" for Stinky Socks
Silver is known for its anti-microbial property for ages. As early as fourth century BC, the great Greek physician Hippocrates described the use of silver...
SEP 26, 2018
Chemistry & Physics
SEP 26, 2018
There's Nothing Weak About the Weak Force
The weak nuclear force, or weak force for short, is so named because it is the direct contrast to the strong nuclear force, the attractive force that binds...
SEP 27, 2018
Videos
SEP 27, 2018
Should Governments Get Involved in Obesity?
Obesity is a growing problem, for children as well as for adults. In the UK, there is a concern about the rates of childhood obesity. Public health officia...
OCT 01, 2018
Space & Astronomy
OCT 01, 2018
Getting to Alpha Centauri Won't Be Easy, But...
Alpha Centauri is one of our closest stellar neighbors at just 4.22 light years away, and astronomers think there’s an exoplanet orbiting the host st...
OCT 06, 2018
Videos
OCT 06, 2018
Explore a Human Cell with an Interactive Website
The Allen Institute is aiming to enhance our understanding of how human cells function....
Loading Comments...